#include <memory.h> 
#include <stdio.h>
#include "md5.h" 
 

typedef struct
{
    unsigned int count[2];
    unsigned int state[4];
    unsigned char buffer[64];
}MD5_CTX;


#define F(x,y,z) ((x & y) | (~x & z))
#define G(x,y,z) ((x & z) | (y & ~z))
#define H(x,y,z) (x^y^z)
#define I(x,y,z) (y ^ (x | ~z))
#define ROTATE_LEFT(x,n) ((x << n) | (x >> (32-n)))
#define FF(a,b,c,d,x,s,ac) \
          { \
          a += F(b,c,d) + x + ac; \
          a = ROTATE_LEFT(a,s); \
          a += b; \
          }
#define GG(a,b,c,d,x,s,ac) \
          { \
          a += G(b,c,d) + x + ac; \
          a = ROTATE_LEFT(a,s); \
          a += b; \
          } 
#define HH(a,b,c,d,x,s,ac) \
          { \
          a += H(b,c,d) + x + ac; \
          a = ROTATE_LEFT(a,s); \
          a += b; \
          } 
#define II(a,b,c,d,x,s,ac) \
          { \
          a += I(b,c,d) + x + ac; \
          a = ROTATE_LEFT(a,s); \
          a += b; \
          } 


static void MD5Init(MD5_CTX *context);
static void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen);
static void MD5Final(MD5_CTX *context,unsigned char digest[16]);
static void MD5Transform(unsigned int state[4],unsigned char block[64]);
static void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len);
static void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len);


static unsigned char PADDING[]={0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 
                         0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 
                         0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 
                         0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; 
                          
static void MD5Init(MD5_CTX *context) 
{ 
     context->count[0] = 0; 
     context->count[1] = 0; 
     context->state[0] = 0x67452301; 
     context->state[1] = 0xEFCDAB89; 
     context->state[2] = 0x98BADCFE; 
     context->state[3] = 0x10325476; 
} 


static void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen) 
{ 
    unsigned int i = 0,index = 0,partlen = 0; 
    index = (context->count[0] >> 3) & 0x3F; 
    partlen = 64 - index; 
    context->count[0] += inputlen << 3; 
    if(context->count[0] < (inputlen << 3)) 
       context->count[1]++; 
    context->count[1] += inputlen >> 29; 
     
    if(inputlen >= partlen) 
    { 
       memcpy(&context->buffer[index],input,partlen); 
       MD5Transform(context->state,context->buffer); 
       for(i = partlen;i+64 <= inputlen;i+=64) 
           MD5Transform(context->state,&input[i]); 
       index = 0;         
    }   
    else 
    { 
        i = 0; 
    } 
    memcpy(&context->buffer[index],&input[i],inputlen-i); 
} 


static void MD5Final(MD5_CTX *context,unsigned char digest[16]) 
{ 
    unsigned int index = 0,padlen = 0; 
    unsigned char bits[8]; 
    index = (context->count[0] >> 3) & 0x3F; 
    padlen = (index < 56)?(56-index):(120-index); 
    MD5Encode(bits,context->count,8); 
    MD5Update(context,PADDING,padlen); 
    MD5Update(context,bits,8); 
    MD5Encode(digest,context->state,16); 
} 


static void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len) 
{ 
    unsigned int i = 0,j = 0; 
    while(j < len) 
    { 
         output[j] = input[i] & 0xFF;   
         output[j+1] = (input[i] >> 8) & 0xFF; 
         output[j+2] = (input[i] >> 16) & 0xFF; 
         output[j+3] = (input[i] >> 24) & 0xFF; 
         i++; 
         j+=4; 
    } 
} 


static void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len) 
{ 
     unsigned int i = 0,j = 0; 
     while(j < len) 
     { 
           output[i] = (input[j]) | 
                       (input[j+1] << 8) | 
                       (input[j+2] << 16) | 
                       (input[j+3] << 24); 
           i++; 
           j+=4;  
     } 
} 


static void MD5Transform(unsigned int state[4],unsigned char block[64]) 
{ 
     unsigned int a = state[0]; 
     unsigned int b = state[1]; 
     unsigned int c = state[2]; 
     unsigned int d = state[3]; 
     unsigned int x[64]; 
     MD5Decode(x,block,64); 
     FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */ 
 FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */ 
 FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */ 
 FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */ 
 FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */ 
 FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */ 
 FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */ 
 FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */ 
 FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */ 
 FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */ 
 FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */ 
 FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */ 
 FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */ 
 FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */ 
 FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */ 
 FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */ 
  
 /* Round 2 */ 
 GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */ 
 GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */ 
 GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */ 
 GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */ 
 GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */ 
 GG(d, a, b, c, x[10], 9,  0x2441453); /* 22 */ 
 GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */ 
 GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */ 
 GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */ 
 GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */ 
 GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */ 
 GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */ 
 GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */ 
 GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */ 
 GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */ 
 GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */ 
  
 /* Round 3 */ 
 HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */ 
 HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */ 
 HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */ 
 HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */ 
 HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */ 
 HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */ 
 HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */ 
 HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */ 
 HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */ 
 HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */ 
 HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */ 
 HH(b, c, d, a, x[ 6], 23,  0x4881d05); /* 44 */ 
 HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */ 
 HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */ 
 HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */ 
 HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */ 
  
 /* Round 4 */ 
 II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */ 
 II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */ 
 II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */ 
 II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */ 
 II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */ 
 II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */ 
 II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */ 
 II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */ 
 II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */ 
 II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */ 
 II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */ 
 II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */ 
 II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */ 
 II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */ 
 II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */ 
 II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */ 
     state[0] += a; 
     state[1] += b; 
     state[2] += c; 
     state[3] += d; 
} 


const char* md5_encode(const void* buff, unsigned long size)
{
    MD5_CTX jiaqi;
    unsigned char md5_value[16];
	static char result[33];

        MD5Init(&jiaqi);

        MD5Update(&jiaqi, (unsigned char *)buff, size);

        MD5Final(&jiaqi, md5_value);

        for(int i = 0; i < 16; i++)
                sprintf(result + i * 2, "%02x", md5_value[i]);

	return result;
}

